Percussive rock drill



L n Y R HD mm Em BE mm P% .U m E P Oct. 16, 1928.

Filed March 24, 1927 I l l l I I l l l l Patented st. 16, 1928.

UNETED STATES ERNEST PENBERTHY, OF REDRUTH, CORNWALL, ENG-LAND, ASSIGNOR TO THE CLL MAX ROCK DRILL & ENGINEERING COMPANY OF GREAT BRITAIN.

PER-CUSE-ZIVE Application filed March 24, 1927, Serial No.

This invention relates to percussive rock drills and has forits object to provide van improved method of retaining and holding the valve bushings against movement.

According to the present invention the valve bushings are retained and held from movement at one end by means of a division ring and at the other end by the cover for the cylinder of the hammer piston, said ring and cover being for this purpose preterahly provided with projections enganimg with corresponding; shoulders on the valve bushings. rein example of construction in accordance with the invention is illustrated. in the accempanying drawings wherein Figure 1 shows a longitudinal section of a percussive rock drill with the invention applied thereto, and

Figure 2 shows a section'on the line 2-2 of Figure 1.

According to one example ot construction as applied to pneumatic rock drills, valve bushings 2O, 2]. are fitted into the ends of the valve casing 7 and the bushing 20 at one end is held in position and prevented from displacement by a projection 2'? formed on the division ring 28 which is located between the cylinder 10 of the hammer piston 11 and the guide 29 for the drill .30. The pro 30 jection 27 on this division ring 28 when in position engages with a shoulder portion :31. on the valve bushing 20 and thus prevents PATENT OFFICE.

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178,022, and in Great Britain April 21,1926.

any rotation thereof. The valve bushing; 21 at the other end of the valve chamber 7 is held. in position by means of the cover plate 32 for the end of the cylinder 10 of the hammer piston 11 which is also provided with a shouldered projection 33 adapted to engage with a correspondingshoulder 34 on the valve hushingJ Having thus described my invention what claim as new and desire to secure by Letters Patent is z- In a percussive rock drill a hammer cylinder, a valve chamber mounted on said hammer cylinder, two bushings fitted one into each end of said valve chamber, shoulders on said bushings, said shoulders iaving an engaging face extending in a plane at right angles to the longitudinal axis of the bushings and at an angle to the horizontal, an annular dividing; ring at one end oi. said hammer cylinder, an annular end cover on the other end of said hammer cylinder, and projections, one on the said dividing; ring and one on the said end cover,

said projections extending laterally from said dividing ring; and said end cover, said projections having engaging; faces, which are complementary to the engaging faces of the shoulders and ("o-operate therewith for the purpose of retaining the bushings in position and preventing movement thereof.

ERNEST PENBERTHY. 

